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3 years ago

Cold air rises and warm air sinks. True or False

Chemistry

1 answer:

Korvikt [17]3 years ago

7 0

Answer:

false

Explanation:

warm air goes up and cold air sinks, imagine a hot air balloon and how it works, the fire releases the warm air into the balloon itself and rises on how much fire is released.

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Why is the layer of fat on top

mihalych1998 [28]

Answer:

The solid layer of fat on top protects the broth from freezer burn. When I take the broth out of the freezer I use a butter knife to pop the fat cap off before defrosting. I do save chicken fat from soup and use it instead of butter or olive oil when I cook onions.

Explanation:

hit the heart

5 0

3 years ago

In the laboratory a general chemistry student finds that when 2.84 g of KClO4(s) are dissolved in 107.70 g of water, the tempera

vredina [299]

Answer : The enthalpy change of dissolution of $KClO_4$ is 54.3 kJ/mole

Explanation :

Heat released by the reaction = Heat absorbed by the calorimeter + Heat absorbed by the water

$q=[q_1+q_2]$

$q=[c_1\times \Delta T+m_2\times c_2\times \Delta T]$

where,

q = heat released by the reaction

$q_1$ = heat absorbed by the calorimeter

$q_2$ = heat absorbed by the water

$c_1$ = specific heat of calorimeter = $1.55J/^oC$

$c_2$ = specific heat of water = $4.184J/g^oC$

$m_2$ = mass of water = 107.70 g

$\Delta T$ = change in temperature = $T_2-T_1=(22.80-20.34)=2.46^oC$

Now put all the given values in the above formula, we get:

$q=[(1.55J/^oC\times 2.46^oC)+(107.70g\times 4.184J/g^oC\times 2.46^oC)]$

$q=1112.3J=1.1123kJ$

Now we have to calculate the enthalpy change of dissolution of $KClO_4$

$\Delta H=\frac{q}{n}$

where,

$\Delta H$ = enthalpy change = ?

q = heat released = 1.1123 kJ

m = mass of $KClO_4$ = 2.84 g

Molar mass of $KClO_4$ = 138.55 g/mol

$\text{Moles of }KClO_4=\frac{\text{Mass of }KClO_4}{\text{Molar mass of }KClO_4}=\frac{2.84g}{138.55g/mole}=0.0205mole$

$\Delta H=\frac{1.1123kJ}{0.0205mole}=54.3kJ/mole$

Therefore, the enthalpy change of dissolution of $KClO_4$ is 54.3 kJ/mole

5 0

4 years ago

Guys, please, please help!!

shutvik [7]

Ookay

1) T
2) T
3) F

Hope i helped :)

6 0

3 years ago

Read 2 more answers

How did Dalton describe the relationship between atoms and elements? An element is made up of one kind of atom. Atoms are made u

victus00 [196]

Answer: An element os made up of one kind of atom.

Explanation: Dalton's concept states that all atoms of an element is identical.

5 0

3 years ago

Read 2 more answers

Hydrogen fluoride is used:

Simora [160]

Answer: The correct answer is option B)

in the synthesis of cryolite for aluminum production.

Explanation:

Hydrogen fluoride (HF) is used in synthesis of cryolite for aluminum production.

HF is a gas that dissolves in water to form hydrofluoric acid. However, HF also react with halogenated alkanes like trichloromethane CHCl3 to form organofluorine compounds that serves as precursors in the synthesis of cryolite, an Ore from which aluminum is produced

6 0

3 years ago